HP 48G Series Quick Start Manual page 60

Step 1: You're already working with RATFUNC, and the =: variable
field is highlighted, so you are ready to enter the guess.
2 (7) (ENTER)
ENTER FUNCTION TO SOLVE
[ECT[CHOOZ]| LEER
Step 2: Solve for : again and examine the new solution.
SOLVE ERUATIOM 33
Se NS ed oo
Ec:
ue BIE
-3. B8000AEEEE 1
Sian Rewersal
ENTER VALUE OR PRESS SOLVE
I I ET
Step 3: Press iE to remove the message box.
Interpreting the Results
The Sian Esuverzal message means that the solver has found two
adjacent sample points at which the value of the expression is opposite
in sign, but hasn't found one sample point that makes the expression
zero (to 12 digits). This can happen at a legitimate solution—the
finite numerical precision making it impossible for the HP 48 to find
the actual zero. But it can also occur at a discontinuity, where the
graph of the equation "jumps" across the x-axis without ever touching
it.
Two kinds of Sign Reversals
BY
5
FCN EDIT JeANCL
7
Actual Root Discontinuity
ET]GE TE
5-4 Solving Equations